I don’t know how to fix this issue that you are having! Only solution I have for you is to uninstall Avast Online Security. In the past and I think currently users are having issues with it. Simply go to add/remove right click on avast, click on change, click next, and uncheck Browser protection, and click next. It will uninstall Avast Online Security for you. After that manually restart your computer.
Uninstalling Avast Online Security won’t affect your computer from online threats.